This type of heat exchanger conventionally includes a heat exchanger formed by stacking a heat transfer plate and a spacer without bonding in order to suppress the manufacturing cost while enhancing the basic function such as ventilation resistance and heat conversion efficiency. This is disclosed in patent document 1 and the like. The heat exchanger will be described below with reference to FIG. 20A, FIG. 20B, and FIG. 21.
As shown in such figures, spacer 101 made of synthetic resin includes spacing rib 103 for holding a spacing between heat transfer plates 102, coupling rib 104 for coupling spacing ribs 103, and small projection 105 arranged on spacing rib 103 and coupling rib 104. The opposing surfaces of the spacer stacked one above the other include convex part 106 and concave par 107 that fit to each other and are integrally molded. Heat transfer plate 102 having heat transfer property and moisture permeability, or having only heat transfer property includes alignment hole 108. Alignment hole 108 fits with small projection 105 when spacer 101 and heat transfer plate 102 are stacked.
Heat exchanger 109 is obtained by stacking spacer 101 while alternately shifting by 90 degrees, and interposing heat transfer plate 102 between spacers 101. Heat exchanger 109 couples and holds spacers 101 by fitting convex part 106 and concave part 107 arranged at four corners of spacer 101.
When primary air current A and second air current B are flowed in the above-described configuration, heat is exchanged between primary air current A and secondary air current B through heat transfer plate 102.
Since such conventional heat exchanger 109 is obtained by stacking spacer 101 and heat transfer plate 102 without joining the same, a problem arises in that leakage of air current increases due to lowering in sealing property caused by the shift in stacking, and thus prevention of the leakage of air current due to lowering in sealing property caused by the shift in stacking is demanded.
Since heat exchanger 109 is formed by separately using two components of spacer 101 made of synthetic resin and heat transfer plate 102, the number of components becomes large, the processing step increases, and the manufacturing cost becomes high, and thus reduction of the manufacturing cost by reducing the number of components and reducing the processing steps is demanded.
Furthermore, heat exchanger 109 has a configuration of coupling and holding spacers 101 by fitting convex part 106 and concave part 107 arranged at four corners of spacer 101, but a problem arises in the step of stacking spacers 101 while alternately shifting by 90 degrees. If spacer 101 is stacked in the same direction, spacer 101 is coupled and held even in the incorrect stacking direction as convex part 106 and concave part 107 of spacer 101 are provided for the purpose of coupling and holding. In this case, heat exchanger 109 has a ventilation path formed in the same direction for every heat transfer plate 102, where heat cannot be exchanged at the incorrectly stacked portion when primary air current A and secondary air current B are flowed to heat exchanger 109. Thus, due to incorrect stacking of spacers 101, a problem arises in that heat conversion efficiency lowers due to the matter that the ventilation path cannot be correctly formed for every heat transfer plate 102. Therefore prevention of the lowering of heat conversion efficiency caused by the matter that the ventilation path cannot be correctly formed is demanded.
Moreover, since heat exchanger 109 alternately stacks spacer 101 in the same direction and couples and holds the same even in the incorrect stacking direction, production failure such as incorrect stacking occurs and mass productivity lowers, and thus enhancement of mass productivity by eliminating incorrect stacking of unit elements is demanded.    [Patent document 1] Japanese Patent No. 3,023,546